Auto-Faring behavior change request

[otaku]

Hi,

I’m using DS Pro now and am glad to finally have become a supporting member/user.

In DS Free, i never got to explore the automated fairing early on since it is disabled. So, i faired by hand. Once i began experimenting with the DS Pro Demo version, i noticed that automatic fairing did something differently than simply fairing by hand.

Automated fairing shifts points fore or aft of the gunwhale & keel edges’ points. This is good and well for fairing a hull when the user is not importing the dxf 3d mesh and trying to use that as the basis of a side shell for a given segment of the hull.

I’d like to request that there be a way to prevent DS Pro from shifting nodes forward or aft. I request this because when fairing automatically, the surface takes on a skew that is not friendly to the bulkheads positions i set in Delftship. I set “bulkheads” by using the stations input section and i include the fore/aft faces coordinates to obtain thickness that i’ll create in Punch! ViaCAD and Shark FX. As long as the shell lines up neatly with my stations, i can neatly convert the DXF 3D mesh into a surface.

I’ll post images later when i get the chance.

The first two wireframes show before automatic fairing and after automatic fairing. The first shaded-mode image shows after automatic fairing. The second shaded-mode image shows the hull before any automatic fairing, and this is what i’d like to retain. I don’t mind the y axis points moving, but i want x and z to not be moved. This would permit me to take the sideshell exported from DS Pro as DXF 3D mesh and import it to ViaCAD or Shark FX, then convert them to surfaces, and have those surfaces “appear” as sideshell produced with horizontal welds as often as possible.

Thanks!

Attachments:

• 01_before_automatic_fairing_800x600.jpg
• 01_before_automatic_fairing_800x600.jpeg
• 02_after_automatic_fairing_800x600.jpg
• 03_after_automatic_fairing_648_480.jpg
• 04_after_automatic_fairing_640x480.jpg

[MICHAEL KERR]

Delftship is used to create hull and superstructure surfaces. To achieve a
fair hull the control net has to be as simple as possible (look at the default
hull under File–>New). You will notice that the hull has only 3 longitudial
lines between the sheer and center line and 4 transverse lines between the
bow and stern, thats all you need. The program can create stations which
can be exported to other 3D programs. I believe you can export the stations
via the 2d polylines that just export the stations and exclude the rest
(Ive only done it once myself). If you want to create bulkheads
for export place one station at the beginning of you bulkhead and one where it
will end eg as a 3/4inch or 19mm thick bulkhead, one face will be at say 2.ooo
meters from the stern and the the other face 2.019meters this can be
exported to other 3d programs as a 3/4 inch bulkhead where you can reduce
the hull thickness from it and place openings, doors etc. Dont try to
place bulkheads with control points in Delft or you will end up doing what
the program wasnt designed and almost impossible to fair and a
large migraine. I export 3D polylines into Rhino and the whole lot can be
exported as long as its turned ON.

[otaku]

Hi Mike,

Thanks.

I do turn on the various items to be able to export the DXF 3D Polylines and the DXF 3D Mesh. As to the “bulkheads”, i don’t actually create the faces in DS. I just go into the stations editor and enter the positions. I probably could skip using the curves themselves, but they make for nice visual cues.

But, in CAD, i don’t think the CAD apps can truly make a faithful hull surface that skin-matches what DS produces. But, since the fairing i need is to get the hydros in want, i think i need far more than a handful of points. I need to sculpt the sonar dome, and i am considering making the sideshell flat but angled outward (or radar cross-section reflection reduction reasons), and i don’t like the extra facets or the curvature introduced as visible in the attachments.

[Author]

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